Background
Silicones are unique materials combining the properties of both inorganic and organic compounds. They exhibit low surface tension, low viscosity-temperature coefficient, high compressibility, high gas permeability, as well as excellent resistance to temperature extremes, oxidation, weathering, water, and chemicals. They are also non-toxic, physiologically inert, and possess excellent dielectric properties.
Silicone products are widely used for sealing, adhesion, lubrication, coatings, surfactants, defoaming, waterproofing, insulation, and as fillers. The production of silicones involves a complex multi-step process:
• Silica and carbon are converted at high temperature into siloxanes.
• Metal siloxane intermediates are chlorinated, yielding chlorosilanes.
• Hydrolysis of chlorosilanes produces siloxane units along with HCl, which are then distilled and purified.
• These intermediates form silicone oils, resins, elastomers, and other polymers with different solubility and performance properties.
Throughout this process, manufacturers must remove unwanted residues, water, and gel particles to ensure product quality. Stable, efficient, and easy-to-maintain filtration systems are therefore essential.
Customer Challenge
A silicone manufacturer required a more effective method to separate solids and trace water during production. Their process uses sodium carbonate to neutralize hydrogen chloride, which generates residual water and solids. Without efficient removal, these residues can form gels, increasing product viscosity and compromising quality.
Traditionally, this purification requires two steps:
• Separate solids from silicone intermediates.
• Use additives to remove water.
The customer sought a single-step solution capable of removing solids, trace water, and gels, thereby simplifying the process, reducing byproduct waste, and improving production efficiency.
Solution
Great Wall Filtration developed the SCP Series Depth Filter Modules, designed to remove solids, residual water, and gel particles in a single step.
• Technology: The SCP modules combine fine cellulose fibers (from deciduous and coniferous trees) with high-quality diatomaceous earth and cationic charge carriers.
• Retention Range: Nominal filtration rating from 0.1 to 40 µm.
• Optimized Performance: Tests identified the SCPA090D16V16S module with 1.5 µm retention as the most suitable for this application.
• Mechanism: Strong adsorption capacity for water combined with an ideal pore structure ensures reliable retention of gels and deformable particles.
• System Design: Installed in stainless steel, closed housing systems with filter areas from 0.36 m² to 11.7 m², offering flexibility and easy cleaning.
Results
• Achieved effective single-step removal of solids, trace water, and gels.
• Simplified production workflow, eliminating the need for two separate processes.
• Reduced byproduct waste and improved production efficiency.
• Delivered stable, reliable filtration performance without significant pressure drop.
Outlook
FAQ
Q1: Why is filtration critical in silicone production?
Filtration ensures the removal of unwanted solids, trace water, and gel particles that can negatively impact product quality, stability, and viscosity. Without effective filtration, silicones may fail to meet performance standards.
Q2: What challenges do manufacturers face in silicone purification?
Traditional methods require multiple steps—separating solids and then using additives to remove water. This process is time-consuming, costly, and can generate additional waste.
Q3: How does the SCP Series Depth Filter Module solve these issues?
The SCP modules enable single-step filtration, effectively removing solids, residual water, and gels. This simplifies the process, reduces waste, and enhances overall production efficiency.
Q4: What is the filtration mechanism of SCP modules?
SCP modules use a composite structure of fine cellulose fibers, high-quality diatomaceous earth, and cationic charge carriers. This combination ensures strong adsorption of water and reliable retention of gels and deformable particles.
Q5: What retention ratings are available?
SCP modules offer a nominal filtration range from 0.1 µm to 40 µm. For silicone processing, the SCPA090D16V16S module with a 1.5 µm retention rating is often recommended.
